Dual pump



April 1966 R. E. SHELHART 7 3,244,111

DUAL PUMP 2 Sheets-Sheet 1 Filed Sept. 14, 1965 INVENTOR ROBERT E. SHELHART ATTORNEY! April 5, 1966 R. E. SHELHART DUAL PUMP v 2 Sheets-Sheet 2 Filed Sept. 14, 1965 INVENTOR ROBERT E. SHELHART ATTORNEY)" United States Patent 3,244,111 DUAL PUMP Robert E. Shelhart, Dearborn, Mich, assignor to Dura Corporation, Oak Park, Mich, a corporation of Michigan Filed Sept. 14, 1965, Ser. No. 487,133 4 (Ilaims. (Cl. 103-126) This application is a continuation-in-part of application Serial No. 299,555, filed August 2, 1963, for Dual Pump, now abandoned.

This invention relates to fluid pumps in general and more particularly to dual pump units having a common drive power source and reservoir system.

There are numerous instances where two fluid pumps are required to drive separate or cooperative mechanism and the pumps must be synchronized for one reason or another. One such instances is in the operation of folding top structures of convertible type automotive vehicles.

Most power operated folding top structures for convertible type automotive vehicles make use of separate hydraulic power cylinders, one on each side of the vehicle, to operate the different side rail lift mechanisms for the top structure. Each cylinder is double acting and requires hydraulic fluid to be supplied and depleted, alternately, from opposite ends thereof and for any fluid deficiency to be replenished from a reservoir source. The operation of the cylinders must be synchronized to prevent racking or twisting of the top structure.

Generally, separate fluid supply pumps have been used for the different cylinders to preclude any cross transfer of fluid from one to the other. In addition, separate drive motors have been used for each pump with the synchronization of the fluid cylinders obtained through the synchronization of the drive motors.

Although manufacturers have been able to devise a compact unit which makes use of a common reservoir, with suitable check valves to preclude a cross transfer of fluid, there is still a major duplication of equipment in the dual pumps and motors required and no change in the problems of synchronizing the two systems. As in the past with a completely separate motor, pump and reservoir systems, synchronization is still dependent upon the braking effect imposed by one system upon the motor of the other system. i

It is an object of this invention to provide a dual fluid pump system having the different pumps driven by a common drive motor.

More particularly, .it is an object of this invention to provide a pair of rotor pumps having the rotors of each driven by a common motor drive shaft.

As will be shown, this eliminates the cost of a second drive motor, reduces the overall size of the unit, simplifies assembly, with considerable savings in this regard, and has the advantage of direct drive synchronization of the pump units.

It is an object of this invention to provide separate fluid pumps in a common housing and have the pump rotors of each provided in a common chamber.

It is an object of this invention to provide separate communicating fluid passage means for each fluid pump and to make use of a common reservoir, without a crosstransfer of fluid between the pumps either within the common rotor chamber or elsewhere in the system.

The objects of the invention are provided by .a dual pump assembly comprising a housing having a single cylindrical pump cavity therein, a single drive shaft extending eccentrically into said pump cavity, a pair of inner pump rotors secured to rotate in the pump cavity with the shaft, said pair of inner pump rotors being 3,244,111 Patented Apr. 5, 1966 positioned on said shaft in axially spaced relationship, a pair of outer pump rotors positioned in said cavity in axially spaced side by side relationship and radially opposite to said pair of inner pump rotors, cooperating teeth on said inner and outer rotors to provide a drive connection therebetween and to provide a pair of variable volume pump chambers, and freely rotatable annular sealing means journaled on said shaft, said sealing means extending between the pair of inner and outer pump rotors and dividing said cylindrical pump cavity into separate pump chambers and separate pressure fluid supply and exhaust passages for each of said pair of variable volume pump chambers.

These and other objects and advantages to be gained in the practice of this invention will be better understood and appreciated upon a reading of the following specification in regard to a preferred embodiment of the invention and having reference to the accompanying drawings wherein:

FIGURE 1 is a side elevation and partially crosssectioned view, substantially on line 1-1 of FIGURE 4, of the dual fluid pump arrangement provided by this invention showing a single drive motor and fluid reservoir used therewith.

FIGURE 2 is an enlarged exploded view of the dual pump rotors and annular sealing means.

FIGURE 3 is an enlarged fragmentary view of the pumping chamber, substantially on line 3-3 of FIG- URE 1.

FIGURE 4 is a cross-sectional view of the pump assembly shown by FIGURE 1, taken in the plane of line 4-4 thereon and looking in the direction of the arrow-s with the inner rotor members and spacer removed.

FIGURE 5 is a cross-sectional view of the pump assembly shown by FIGURE 1, as seen in the plane of line 5-5 and looking in the direction of the arrows thereon. FIGURE 6 is an enlarged, cross-sectional and fragmentary detail view of a feature of the pump assembly of this invention as seen in the plane of line 6-6 of FIGURE 5 and looking in the direction of thearrows thereon.

FIGURE 7 is a cross-sectional view of the detailed feature of FIGURE 6 as seen in the plane of line 7-7 thereon and looking in the direction of the arrows.

FIGURE 8 is an enlarged, cross-sectional and fragmentary view of a modification in the sealing arrangement between the two pump rotors.

The drawings show a motor and pump assembly 10 which includes a small electrically driven motor 12, which is reversible, connected to one end of a pump assembly 14. The pump assembly in turn includes -a chamber housing 16, combination chamber cover and passage member 18, and a fluid reservoir member 20. The casing or housing 22 of the motor 12 is secured to the chamber housing member 16 of the pump assembly in any suitable and conventionally known manner and the fluid reservoir member 20 is engaged to the cover or passage member 18 as by a centrally disposed tie bolt 24. The pump housing and cover members themselves are engaged together by threaded bolt fasteners 26 extending through the cover member and engaged in tapped holes in the housing member.

The motor 12 has its shaft 28 extended into the housing member 16 of the pump assembly through a centrally disposed passage 3% including journal bearing means and a suitable seal. The shaft extends into a pump chamber space or bore 32 provided in the face of the housing member 16 and which is closed by the cover or passage member 18.

Within the pump chamber space 32 is provided a pair of rotor type pumps 34 and 36 each of which include an internal and external rotor member identified by the numerals 38 and 40, and 38 and 40, and have the drive shaft 28 of the motor 12 engaged with the internal rotor members. The two pumps are co-axially disposed in the common chamber and have a separator 42 provided therebetween. The tolerances of the pump parts and separator are such that the one pump 36 has the rotor members thereof seated against the bottom wall of the chamber bore 32 and the rotor members of the other pump 34 seated against the chamber closing part of the cover member 18 with reasonable clearance for free rotation of the rotor parts and without fluid transfer across the ends of the respective pumps. The separator 42 itself is freeiy rotatable on the rotor drive shaft 28. It overlaps the chamber spaces 44, FIGS. 3 and 4, between the internal and external rotor members of the two pumps and thereby precludes cross fluid transfer between the pumps. The only relative movement between the separator 42 and the pump parts is very small and the wear factor is accordingly negligible.

Fluid passages 46 and 48, FIGS. 1 and 4, are provided through the outer side walls of the housing member 16 of the pump assembly, from threaded recesses 50 and 50 for fluid line fittings, and extend radially inward on diametrically opposite sides of the housing towards the shaft passage 30. They intersect and terminate in communication with arcuate slots 51 and 52 provided through the bottom wall of the chamber bore 32 and which are in turn in communication with the chamber spaces 44 between the rotor members of the pump 56.

It will be appreciated that the fluid passage means just described are in communication with the inlet and outlet sides of the rotor pump 36 and that the different passages serve alternately to supply and carry off fluid circulated by the pump dependent upon the rotational direction imposed by the drive motor 12.

In addition to the fluid passages 46 and 48, and the passage slots 51 and 52, reservoir connecting passages 54 and 56 are provided in the housing member 16 and are disposed to intersect the inlet and outlet passages 46 and 48 between the ends thereof. These passages are only part of the reservoir connecting passage means and the whole reservoir communicating system is best explained in the subsequent discussion.

Referring now to the cover and passage member 18 of the pump assembly 14:

A pair of fluid passages 58 and 60 are provided through diametrically opposite sides of the cover member 18, from threaded recesses 6262' for fittings, and intersect arcuate slots 64 and 66, formed through the pump chamber closing face thereof and aligned with the chamber spaces 44 between the rotor members of the rotor pump 34, in the same manner as the fluid inlet and outlet passage means in the cover member 18. In addition and like manner reservoir connecting passages 68 and 71 are provided in communication with the passages 58 and 60.

From the preceding discussion it will be appreciated that separate and distinct fluid supply and exhausting passage means are provided for each of the rotor pumps 34 and 36; one set of passages being provided in the housing member 16 and the other set in the cover member 18. Although both pumps are provided in the housing member 16, in a common pump chamber 32, and are driven on a common drive shaft 28, the fluid passage means for the pumps are separate so that there is no cross-transfer of fluid therebetween. This holds true in the reservoir communicating passage means for the replenishment of any necessary fluid in the fluid systems for the two pumps as will next be described.

Departing only momentarily from the normal sequence of the description, reference should be made to an alternate form of separator for between the two pumps 34 and 36. Such a separator is shown as a wave spring member 72 in FIGURE 8 which is disposed between the two pumps and is and serves in like capacity to the separator 42 previously described, in combination with the washers 74 and 76 closing the pump spaces 44 between the rotor members. It serves the additional advantage of assuring that the rotor members of the pumps are seated against the end wall of the chamber 32 and cover member 18 and that fluid flow across the ends thereof is precluded Without being overly mindful of close tolerances in the pump rotor parts, chamber bore, etc.

Returning to the reservoir connecting passage means of the two fluid supply and exhaust systems for the pumps 34 and 36, reference should be made to FIGURES 5-7.

The reservoir connecting passages 54 and 56 of the fluid system for pump 36 and the reservoir connecting passages 68 and for the other pump 34 extend to the adjacently disposed faces of the respective housing and cover members within which provided. Here they are respectively in communication with grooves or channels 78, 80, 82 and 84, formed in the face of the cover member 18 and which provide fluid passage means to a set of reservoir connecting passageways 86, 88, and 92 disposed in respectively close relation through the cover or passage member to the fluid chamber space 94 within the reservoir member 26.

A check valve housing member 96 is secured to the back side of the cover member 18. It is disposed within the fluid reservoir chamber space 94 and over the ends of the reservoir connecting passageways 86, 88, 90 and 92. However, there are separate ball check chamber spaces 98 and 98 in communication with each of the passageways and which are formed partly in the check valve housing member 96 and partly in the cover member 18. These each include connecting passages Hi0 and 1th? to the reservoir chamber space 9 5 and are formed to provide ball seats for two pairs of ball check valve members 102 and 102' retained therein.

The reservoir connecting passageways which relate to the same fluid pump system, as passageways 9d and 92 are to the fluid pump 34, have a common rocker arm member 104 for the example given and 106 for the other, which enables only one ball of each set of the ball check members 102-102 to be seated at one time. This assures that the reservoir chamber is open to the inlet side of the pumps but is closed to the outlet side regardless of which of the supply and exhaust passages serves which purpose.

To be more specific in the latter regard, fluid that is drawn into passage 58, in the course of operating the rotor pump 34 in one rotational direction, will draw any additional fluid needed to replenish a deficiency from the reservoir supply by creating a suction through passage 68, groove or channel 32 and passageway 90 which will unseat its ball check 102 and allow the necessary fluid to pass. At the same time, the pressure side of the pump 34 is in communication through passage 71%, groove or channel 84 and passageway 92 to seat the other ball check of check valve member 102. In seating the said other ball check the rocker arm control 164 is activated to assure that the first mentioned ball check is unseated for replenishment supply if required.

The check valve arrangement provided thus essentially assures that fluid is drawn only as necessary to replenish one of the fluid systems and precludes any transfer between the two pumps through the reservoir member itself.

From the foregoing it will be appreciated that a simple, compact, eiflcient and economical means can be readily provided for dual service by two separate and distinct fluid pumps and supply systems Within a common pump housing and with a single drive motor and reservoir chamber member.

Although a preferred embodiment of this invention has been shown and described in detail, it will be appreciated that certain modifications and improvements are within the scope of the teachings set forth. Accordingly, such of these improvements and modifications as are within the spirit of the invention and are not specifically excluded by the language of the hereinafter appended claims, are to be considered as inclusive thereunder.

I claim:

1. A dual pump assembly comprising a housing having a single cylindrical pump cavity therein, a single drive shaft extending eccentrically into said pump cavity, a pair of inner pump rotors secured to rotate in the pump cavity with the shaft, said pair of inner pump rotors being positioned on said shaft in axially spaced relationship, a pair of outer pump rotors positioned in said cavity in axially spaced side by side relationship and radially opposite to said pair of inner pump rotors, cooperating teeth on said inner and outer rotors to provide a drive connection therebetween and to provide a pair of variable volume pump chambers, and freely rotatable annular sealing means journaled on said shaft, said sealing means extending between the pair of inner and outer pump rotors and dividing said cylindrical pump cavity into separate pump chambers and separate pressure fluid supply and exhaust passages for each of said pair of variable volume pump chambers.

2. The dual pump assembly defined in claim 1 wherein said annular sealing means includes a resilient member normally urging said pairs of pump rotors in spaced relationship.

3. The invention defined in claim 1 wherein said annular sealing means includes a pair of spaced discs and spring means urging said discs in to sealing engagement with their respective rotors.

4. A dual pump assembly comprising a housing having a single cylindrical pump cavity therein, a single drive shaft extending eccentrically into said pump cavity, a

reversible motor drivably connected to said shaft, a pair of inner pump rotors secured to rotate in the pump cavity with the shaft, said pair of inner pump rotors being positioned on said shaft in axially spaced relationship, a pair of outer pump rotors positioned in said cavity in axially spaced side by side relationship and radially opposite to said pair of inner pump rotors, cooperating teeth on said inner and outer rotors to provide a drive connection therebetween and to provide a pair of variable volume pump chambers, and freely rotatable annular sealing means journaled on said shaft, said sealing means extending between the pair of inner and outer pump rotors and dividing said cylindrical pump cavity into separate pump chambers, and separate pressure fluid supply and exhaust passages for each of said pair of variable volume pump chambers.

References Cited by the Examiner UNITED STATES PATENTS 2,490,115 12/1949 Clarke 103-120 2,531,808 11/1950 Eames 103--126 2,790,391 4/1957 Holl 103120 2,864,312 12/1958 Shelton et a1. 1033 2,928,243 3/ 1960 Albright 103-3 3,014,429 12/1961 Doble 103-4 3,025,796 3/1962 Miller 103-4 3,106,163 10/1963 Mosbacher 1034 MARK NEWMAN, Primary Examiner.

W. I. GOODLIN, Assistant Examiner. 

1. A DUAL PUMP ASSEMBLY COMPRISING A HOUSING HAVING A SINGLE CYLINDRICAL PUMP CAVITY THEREIN, A SINGLE DRIVE SHAFT EXTENDING ECCENTRICALLY INTO SAID PUMP CAVITY, A PAIR OF INNER PUMP ROTORS SECURED TO ROTATE IN THE PUMP CAVITY WITH THE SHAFT, SAID PAIR OF INNER PUMP ROTORS BEING POSITIONED ON SAID SHAFT IN AXIALLY SPACED RELATIONSHIP, A PAIR OF OUTER PUMP ROTORS POSITIONED IN SAID CAVITY IN AXIALLY SPACED SIDE BY SAID RELATIONSHIP AND RADIALLY OPPOSITE TO SAID PAIR OF INNER PUMP ROTORS, COOPERATING TEETH ON SAID INNER AND OUTER ROTORS TO PROVIDE A DRIVE CONNECTION THEREBETWEEN AND TO PROVIDE A PAIR OF VARIABLE VOLUME PUMP CHAMBERS, AND FREELY ROTATABLE ANNULAR SEALING MEANS JOURNALED ON SAID SHAFT, SAID SEALING MEANS EXTENDING BETWEEN THE PAIR OF INNER AND OUTER PUMP ROTORS AND DIVIDING SAID CYLINDRICAL PUMP CAVITY INTO SEPARATE PUMP CHAMBERS AND SEPARATE PRESSURE FLUID SUPPLY AND EXHAUST PASSAGES FOR EACH OF SAID PAIR OF VARIABLE VOLUME PUMP CHAMBERS. 